1. Field of the Invention
The present invention relates to a foot-actuated control arrangement, in particular for dental apparatuses, including an actuating element acting on a switch or control element, and which is equipped with a treadle. The actuating element is displaceable towards both sides from an initial position in one plane, being displaceable along a pivoted path about a stationary position, and can be restrained through at least one setting or control element in the mentioned initial position along the pivoted path and, subsequent to a displacement from this position, can be automatically returned thereto.
2. Discussion of the Prior Art
A foot-actuated control arrangement of the above-described type has already become known from German Pat. No. 641,306. In this known foot-actuated control arrangement, the actuating element which is constructed as a foot-actuated lever is restrained in its defined initial position through the aid of contact springs. In addition to the applicable foot there is provided a further foot pedal which is drawn in a similar manner into a definite initial position by means of a separate spring. Consequently, these foot levers or actuating elements cannot be restrained in every suitable fixed position along their respective pivoting paths.
Furthermore, a foot pedal starter is known, which includes a latching device which can be extended by means of a push rod; as is disclosed in German Pat. No. 683,037. Hereby, a foot lever is rigidly connected with a latching path which serves for stepped regulating, and wherein the latch element is constructed as a resilient catch member which is fastened on a support base plate. Through the intermediary of a separate spring-loaded actuating element, in the known foot pedal starter the latching member lock which is provided can be rendered either operative or inoperative. However, in every instance, the foot lever is restrained in a definite initial or median position through the action of a resilient resetting device, into which it is automatically returned after its displacement. This known foot pedal starter is also subject to the disadvantage which has been described in connection with the previously considered foot-actuated control arrangement.
Finally, from German Pat. No. 22 31 265 there has also become known a foot-actuated control arrangement of the above-described type, in which the actuating element is restrained in two fixed or stationary positions, which form the corners of a horizontally oriented triangle, whereby the rotation of the actuating element from its stationary position presently effects a corresponding rotational movement about only one stationary position of the two stationary or fixed positions. Also in this known foot-actuated control arrangement, the actuating element is automatically returned into its initial position subsequent to each effected setting.
It has been ascertained that, in many instances, it is inadequate to provide a foot-actuated control arrangement whose actuating element, subsequent to each actuation, is again automatically returned to an initial position. Occasionally, it is necessary or desired that the actuating element of a foot-actuated control arrangement can be maintained in each set position subsequent to the effected setting without causing an automatic return into an initial position. In order to meet that type of requirement, predicated on the above considered known arrangements, there must also be provided separate foot-operated control devices. Inasmuch as for the implementation of the two functions there must be provided practically always two separate foot-actuated control devices, this requires significant constructional demands. In addition thereto, also disadvantageous is the necessarily large spatial requirement, and the danger of possible confusion among the currently provided foot-actuated control devices.